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The purpose was to present a total description, distribution, and ranking of chronic pain conditions in the general population. This was based on structured clinical examinations of a random sample from a population-based survey (HUNT3) with a calculated oversampling of participants with chronic pain. Supplemented with access to hospital reports, the examination was performed by experienced physicians and psychologists using a consistent definition of chronic pain as well as ICD-10- and the new ICD-11-classification. The main findings were that a higher proportion of the 551 participants had chronic pain assessed by clinical examination (399) than by self-report in a survey the same day (337). Among those with examination-verified chronic pain estimated from HUNT3 to represent 27.9% of the general population, 63% had chronic primary pain, 81% musculoskeletal pain, and 77% more than one chronic pain condition. When separating chronic primary from chronic secondary pain according to ICD-11, the weighted prevalence was 17.7% for chronic pain conditions of unknown and 10.2% of known cause. When all the participants’ conditions were accounted for, the most prevalent were nonspecific low back (10.8%) and neck pain (7.6%). Participants with chronic primary pain did not have significantly more psychopathology than those with chronic secondary pain: 14.5% vs. 12.5%. Perspective: Since this study confirms the high prevalence in self-report surveys and indicates that two thirds of chronic pain conditions cannot be explained by underlying diseases, this huge health and societal problem should be solved primarily on a public health level directed towards prevention and rehabilitation.

Chronic widespread pain (CWP) is common and associated with loss of functioning and health. Subjects with chronic nonwidespread pain (CnWP) are at increased risk of developing CWP, but few studies have described the nature of the development over time. We followed a random sample of 3105 participants from the population-based HUNT 3 study with 5 annual measurements of pain over 4 years. Although 29% reported CWP on at least 1 occasion, only 7% reported it consistently on 4 or 5 occasions. The average annual cumulative incidence was 5%, and the recovery rate was 38%. In mutual adjusted analysis, the risk of developing CWP from 1 year to the next was higher in subjects with chronic pain (relative risk [RR] = 2.4; 95% confidence interval [CI]: 1.8-3.4), 2 or more pain regions (RR = 3.3; 95% CI: 2.5-4.4), moderate pain or more (RR = 1.8; 95% CI: 1.5-2.6), and with comorbid chronic disease (RR = 1.6; 95% CI: 1.3-1.9). Developing CWP was associated with a modest concurrent change in self-reported mental and physical health. The risk of developing CWP between the fourth and fifth occasions was 80% lower for subjects without a history of CWP, compared to those with a history of CWP. For subjects without previous CWP, the development was associated with previously reported CnWP, but not with the number of occasions with CnWP, in analyses adjusted for sex, age, and pain severity. A substantial proportion of the new cases of CWP originates from subjects floating below and above the definition for CWP over time and, thus, does not seem to involve major transitions in health.

Pain and depression are episodic conditions that might take a chronic course. They are clearly related, but information on how they influence each other in the process of chronification is limited. Pain catastrophizing is hypothesized to play a role in the development of depression and chronic pain, but few longitudinal studies have investigated their association over a longer term. In this study, a random cohort from the general population (n = 4764) answered questions about pain, catastrophizing, and depression at 5 assessments in yearly intervals. Linear mixed models showed that within persons, increases in pain intensity and catastrophizing were independently associated with increases in depressive symptoms {mean change = -1.12, 95% confidence interval (CI) [-1.32 to -0.91] and -1.29, 95% CI [-1.52 to -1.05], respectively}. In prospective analyses restricted to individuals without depression above cutoff at baseline, chronic pain increased the risk of endorsing depression over the following 4 years (odds ratio = 2.01, 95% CI [1.71-2.37]). Seven percent showed a chronic course of depression, as indicated by scores above cutoff on at least 3 of 5 assessments. The number of years lived with chronic pain was associated with a chronic course of depression, with odds ratios increasing from 1.55 (95% CI [0.87-2.91]) to 14.19 (95% CI [8.99-22.41]) when reporting chronic pain on 2 vs 5 assessments compared with none. The results suggest that when pain intensity or catastrophizing change, depressive symptoms change in the same direction. When pain and catastrophizing become chronic, they seem to be mutually reinforcing determinants for chronic depression.

That certain psychological factors are negatively associated with function in patients with chronic pain is well established. However, few studies have evaluated these factors in individuals with chronic pain from the general population. The aims of this study were to: 1) evaluate the unique associations between catastrophizing and perceived solicitous responses and psychological function, physical function, and insomnia severity in individuals with neuropathic pain, osteoarthritis, or spinal pain in the general population; and 2) determine if diagnosis moderates the associations found. Five hundred fifty-one individuals from the general population underwent examinations with a physician and physiotherapist, and a total of 334 individuals were diagnosed with either neuropathic pain (n = 34), osteoarthritis (n = 78), or spinal pain (n = 222). Results showed that catastrophizing was significantly associated with reduced psychological and physical function, explaining 24% and 2% of the variance respectively, whereas catastrophizing as well as perceived solicitous responding were significantly and uniquely associated with insomnia severity, explaining 8% of the variance. Perceived solicitous responding was significantly negatively associated with insomnia severity. Moderator analyses indicated that: 1) the association between catastrophizing and psychological function was greater among individuals with spinal pain and neuropathic pain than those with osteoarthritis, and 2) the association between catastrophizing and insomnia was greater among individuals with spinal pain and osteoarthritis than those with neuropathic pain. No statistically significant interactions including perceived solicitous responses were found. The findings support earlier findings of an association between catastrophizing and function among individuals with chronic pain in the general population, and suggest that diagnosis may serve a moderating role in some of these associations. Perspective When examining persons with pain in the general population, catastrophizing is associated with several aspects of function, and diagnosis serves as a moderator for these associations. The replication of these associations in the general population support their reliability and generalizability.

Epidemiological studies have to a little extent addressed the potential fluctuations of chronic pain over time, and there is a lack of information about the long-term course of pain using repeated measurements. We wanted to identify different trajectories of pain during 8 waves of follow-up over 4 years among individuals in the general population reporting pain lasting at least 6 months at baseline. Secondarily, we wanted to investigate whether biopsychosocial factors at baseline were associated with the different pain trajectories. Longitudinal Latent Class Analysis was performed to classify a random sample of 1905 participants from a larger population-based study (HUNT3) into groups based on their longitudinal pain severity reporting. A five-class solution gave the best fit. The terms chosen to describe the pain trajectories were: “fluctuating” (n = 586 [31%]), “persistent mild” (n = 449 [24%]), “persistent moderate” (n = 414 [22%]), “persistent severe” (n = 251 [13%]), and “gradual improvement” (n = 205 [11%]). In a multinomial logistic regression model using “gradual improvement” as the reference category, the “persistent moderate”, “persistent severe”, and “fluctuating” pain groups were associated with chronic widespread pain, elevated levels of catastrophizing, and poorer mental health. The “persistent mild” group was associated with sleep difficulties only. This study finds that although most individuals have a stable pain course, individuals in the largest distinct trajectory reports pain that fluctuate between mild and moderate levels, thus fluctuating under and above the chronic pain definition using moderate pain or more as a criterion. Perspective When examining the long-term course of chronic pain in the general population, 5 trajectories emerge. Although most individuals have stable pain, the largest distinct trajectory fluctuated under and above the chronic pain cut-off, using moderate pain or more as a criterion. A dichotomous categorization of chronic pain may be overly simplistic.

Background Epidemiological studies of chronic pain frequently report high prevalence estimates. However, there is little information about the development and natural course of chronic pain. Methods We followed a random sample of participants from a population‐based study (HUNT 3) with annual measures over 4 years. Results Among those without chronic pain at baseline, the probability of developing moderate to severe chronic pain (cumulative incidence) during the first year was 5%, a pain status that was maintained among 38% at the second follow‐up. The probability of developing chronic pain diminished substantially for those who maintained a status of no chronic pain over several years. Subjects with moderate to severe chronic pain at baseline had an 8% probability of recovery into no chronic pain, a status that was maintained for 52% on the second follow‐up. The probability of recovery diminished substantially as a status of chronic pain was prolonged for several years. Pain severity, widespread pain, pain catastrophizing, depression and sleep were significant predictors of future moderate to severe chronic pain, both among subjects with and without chronic pain at baseline. Conclusion These findings suggest that the prognosis is fairly good after a new onset of chronic pain. When the pain has lasted for several years, the prognosis becomes poor. The same social and psychological factors predict new onset and the prognosis of chronic pain. Significance The development and recovery of chronic pain is highly dependent on previous pain. The prognosis of chronic pain may be predicted well when considering its duration in combination with other clinical, social and psychological factors. Targeting modifiable prognostic factors may be particularly important for newly developed chronic pain. Locked until 13.5.2019 due to copyright restrictions. This is the peer reviewed version of the following article: [Development and course of chronic pain over 4 years in the general population: The HUNT pain study], which has been published in final form at [https://doi.org/10.1002/ejp.1243]. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Self-Archiving.

Methods for classifying chronic pain in population studies are highly variable, and prevalence estimates ranges from 11% to 64%. Limited knowledge about the persistence of pain and the validity of recall questions defining chronic pain make findings difficult to interpret and compare. The primary aim of the current study was to characterize the persistence of pain in the general population and to validate recall measures against longitudinal reporting of pain. A random sample of 6419 participants from a population study (the HUNT 3 study in Norway) was invited to report pain on the SF-8 verbal pain rating scale every 3 months over a 12-month period and to report pain lasting more than 6 months at 12-month follow-up. Complete data were obtained from 3364 participants. Pain reporting was highly stable (intraclass correlation 0.66, 95% confidence interval 0.65 to 0.67), and the prevalence of chronic pain varied considerably according to level of severity and persistence: 31% reported mild pain or more, whereas 2% reported severe pain on 4 of 4 consecutive measurements. When defined as moderate pain or more on at least 3 of 4 consecutive measurements, the prevalence was 26%. Compared with the longitudinal classification, a cross-sectional measure of moderate pain or more during the last week on the SF-8 scale presented a sensitivity of 82% and a specificity of 84%, and a sensitivity of 80% and a specificity of 90% when combined with a 6-month recall question. Thus pain reporting in the general population is stable and cross-sectional measures may give valid prevalence estimates of chronic pain.

Purpose: Health-related quality of life (HRQoL) has been characterized as the ultimate goal for health interventions such as physical activity (PA). We assessed how frequency, duration, and intensity of PA were related to HRQoL in younger (

Background The reported prevalence of chronic pain ranges from 11% to 64%, and although consistently high, the calculated economic burden estimates also vary widely between studies. There is no standard way of classifying chronic pain. We have repeated measurements of pain in a longitudinal population study to improve validity ofthe case ascertainment. In this paper, associations between chronic pain and demographic characteristics, self reported health and functioning, work Incapacity and health care use were investigated in a sample from the general Norwegian population. Methods A random sample of 6419 participants from a population study (the HUNT 3 Study) was invited to report pain every three months during a 12 month period. Chronic pain was defined as moderate pain or more (on the SF-8 verbal rating scale) in at least three out of five consecutive measurements. Self reported health and functioning was measured by seven of the eight subscales on the SF-8 health survey (bodily pain was excluded). Health care utilisation during the past 12 months was measured by self report, and included seeing a general practitioner, seeing a medical specialist and seeing other therapists. The survey data was combined with information on income, education, disability pension awards and unemployment by Statistics Norway, which provided data from the National Education database (NUDB) and the Norwegian Labour and Welfare Administration (NAV). Results The total prevalence of chronic pain was 36% (95% CI34-38) among women and 25% (95% CI 22–26) among men. The prevalence increased with age, was higher among people with high BMI, and in people with low income and low educational level. Smoking was also associated with a higher prevalence of chronic pain. Subjects in the chronic pain group had a self-reported health and functioning in the range of 1–2.5 standard deviations below that of those without chronic pain. Among the chronic pain group 52% (95% CI 49–55), of participants reported having seen a medical specialist during the 12 month study period and 49%(95% CI 46–52) had seen other health professionals. The corresponding proportions for the group without chronic pain were 32% (95% CI 29–34) and 22% (95% CI 20–25), respectively. Work incapacity was strongly associated with chronic pain: compared with those not having chronic pain, the probability of being a receiver of disability pension was four times higher for those with chronic pain and the probability of being unemployed was twice has high for those with chronic pain. The population attributable fraction (PAF) suggested that 49% (95% CI 42–54) of the disability pension awards and 20% (13–27) of the unemployment were attributable to chronic pain. Conclusion and implications Chronic pain is a major challenge for authorities and health care providers both on a national, regional and local level and it is an open question how the problem can best be dealt with. However, a better integration of the various treatments and an adequate availability of multidisciplinary treatment seem to be important.

Background: Population-based studies have reported conflicting findings on the relationship between physical activity and pain, and most studies reporting a relationship are cross sectional. Temporal relationships are therefore difficult to infer and associations may be subject to confounding from a variety of other factors. The aim of the current study was to investigate the association between exercise and pain longitudinally and to use within subjects analyses to remove between subjects confounding. Methods: In the population-based HUNT 3 study, participants reported both pain and level of exercise. A random sub-sample of 6419 participants was in addition invited to report their last week pain and exercise every three months over a 12 month period (five measurements in total). We used multilevel mixed effects linear regression analyses to prospectively estimate the association between regular levels of exercise (measured in HUNT 3) and subsequent longitudinal reporting of pain. We also estimated within-subjects associations (i.e. the variation in pain as a function of variation in exercise, over time, within individuals) to avoid confounding from between subject factors. Results: Among those invited to participate (N = 6419), 4219 subjects returned at least two questionnaires. Compared with subjects who reported no or light exercise, those who reported moderate levels of exercise or more at baseline, reported less pain in repeated measures over a 12 month period in analyses adjusted for age, sex,education and smoking. Adjusting for baseline level of pain distinctly attenuated the findings. Within subjects, an increase in exercise was accompanied by a concurrent reduction in intensity of pain. However, we found no indication that exercise level at one occasion was related to pain reporting three months later. Conclusion: This longitudinal population-based study indicates that exercise is associated with lower level of pain and that this association is close in time. © 2013 Landmark et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

The evidence for an association between leisure-time physical activity and prevalence of pain is insufficient. This study investigated associations between frequency, duration, and intensity of recreational exercise and chronic pain in a cross-sectional survey of the adult population of a Norwegian county (the Nord-Trondelag Health Study; HUNT 3). Of the 94,194 invited to participate, complete data were obtained from 46,533 participants. Separate analyses were performed for the working-age population (20-64 years) and the older population (65 years or more). When defined as pain lasting longer than 6 months, and of at least moderate intensity during the past month, the overall prevalence of chronic pain was 29%. We found that increased frequency, duration, and intensity of exercise were associated with less chronic pain in analyses adjusted for age, education, and smoking. For those aged 20-64 years, the prevalence of chronic pain was 10-12% lower for those exercising 1-3 times a week for at least 30 minutes duration or of moderate intensity, relative to those not exercising. Dependent on the load of exercise, the prevalence of chronic pain was 21-38% lower among older women who exercised, relative to those not exercising. Similar, but somewhat weaker, associations were seen for older men. This study shows consistent and linear associations between frequency, duration, and intensity of recreational exercise and chronic pain for the older population, and associations without an apparent linear shape for the working-age population.

Background Little is known about contextual effects on chronic pain, and how vulnerability factors influence pain in different contexts. We wanted to examine if fibromyalgia (FM) pain varied between two social contexts, i.e. at home versus in a doctor office, when it was measured the same day, and if pain was stable for 14 years when measured in similar contexts (doctor office). Our secondary aim was to explore if pain vulnerability factors varied in the two different contexts. Findings Fifty-five female FM patients were included in the study and scored pain in both contexts at baseline. Their age ranged between 21–68 years (mean 45.7), mean education level was 11 years and mean FM-duration was 15.6 years. Their mean pain was perceived significantly lower at home than in a doctor context the same day. However, pain was much more stable when measured in two similar contexts 14 year apart where 30 subjects (54.5%) completed. Predictor analyses revealed that pain vulnerability factors apparently varied by home and doctor contexts. Conclusion Pain and pain predictors seem to vary by contexts and time, with less pain at home than to a doctor the same day, but with unchanged pain in the same context after 14 years. Thus, contextual pain cues should be accounted for when pain is measured and treated, e.g. by focusing more on home-measured pain and by optimizing the doctor office context. This explorative study should be followed up by a larger full-scale study. © 2012 Fors et al.; licensee BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.